Alarm system



Jan. 23, 1962 G. H. POHM 3,018,379

ALARM SYSTEM Filed June 5, 1959 I; 29 /28 23/ ALARM GEORGE H. POHM ATTORNEY United States PatentY C) 3,018,379 ALARM SYSTEM George H. Pohm, Lorain, Ohio, assignor to Lorain Products Corporation. a corporation of Ohio Filed June 3. 1959. Ser. No. 817,921 13 Claims. (Cl. 307-46) My invention relates to electrical alarm systems and is directed more particularly to such systems capable of informing the operator whether supplementary, intermittently operating demand devices are properly performing their aiding function in an electrical circuit.

While my invention is adaptable to a wide variety of electrical circuits of the type including a main or continuously operating device and one or more intermittently operating, supplementary devices which are sequentially incorporated in the circuit upon demand of the main device, it will be treated herein, for exemplary purposes, as a part of a constant voltage, automatic battery charging circuit.

More specifically, as applied to a battery charging circuit, my invention contemplates the use of cut-in relays which are responsive to a predetermined increase in load current passing through the main, constant voltage charger. These relays sequentially close the circuit through current supply devices which, when connected into the circuit, bear their rated share of the load to thus maintain current flow through the main, constant voltage device at a value less than the rated current output thereof.

It is customary in such electrical circuits to provide suitable alarm means in the constant voltage device whereby the operator is advised immediately of the fact that the battery charging operation is not proceeding satisfactorily due to breakdown of the main, constant voltage device. However such alarm systems are not satisfactory for, and in fact, are incapable of indicating that the constant voltage device is in operative condition while aiding, supplementary, current supply device or devices have failed. Under the latter conditions it will be seen that the main, constant voltage device will be subjected to the increased current or will shut off pro tectively by means of its own circuitry if the charging circuit is not serviced or replaced immediately upon breakdown of a supplementary current supply device. Under such circumstances, the entire charging operation becomes ineffective.

It is a principal object of my invention to provide, in an electrical circuit, improved means for operating an ancillary electrical system.

An important object of my invention is to provide a simple and economical ancillary, electrical system capable of indicating failure or becoming energized upon the failure of a supplementary power supply means in the presence of an operative, main power supply means.

More specifically, it is an object of my invention to provide an improved, ancillary alarm system for an electrical circuitincluding a main, constant voltage supply means and supplementary, current supply means whereby failure of the current supply means is indicated while the main supply means remains operative, but, because of said failure, is being subjected to current overload conditions.

vvIt is a further object of my invention to provide an improved ancillary alarm system for an electrical circuit including main power supply means and supplementary power supply means, the ancillary system being maintained de-energized when the main supply means is operative and not subjected to overload conditions or when the main supply means is operative and supplementary means has been satisfactorily incorporated in the circuit to perform its load sharing activity, but which is energized to create an alarm or perform some other useful function when the main device is fully operative but is subjected to overload conditions in the presence of failure of the supplementary means to share its portion of the load current.

It is a further object of my invention to provide, in an electrical circuit of the type having main power supply means, supplementary current supply means and means for incorporating the supplementary means in the circuit when current through the main supply means exceeds a predetermined magnitude, an improved alarm system energized by said excessive current in the absence of current flow through the supplementary means.

Another object of my invention is to provide, in a circuit of the above character, an improved alarm system including an alarm operating circuit havingy first current responsive means which is responsive to current flow through the main supply device and capable of energizing the alarm circuit upon flow of excessive current through that device and second current responsive means arranged in opposition to the first and responsive to current ow through the supplementary device to can-fcel the alarm circuit energizing effect of the first means upon current flow through the supplementary device.

It is a further object of my invention to provide an alarm operating circuit of the above character including a relay having a winding thereon which is subjected to current liowing through the main supply means and an opposed winding thereon which is subjected to current flowing through the supplementary means, the first winding being arranged to operate the relay when excessive current flows through the main supply means and the second winding being arranged to neutralize the operating effect of the first winding when current flows simultaneously through the supplementary means and the main means.

It is still another object of my invention to provide, in a circuit having main power supply means and supplementary current supply means, first current responsive means arranged to operate and incorporate into the circuit, the supplementary means when current flow through the main supply means attains substantially its rated current output, second current responsive means arranged to operate and energize an alarm circuit when current of a magnitude greater than the operating current of said first current responsive means fiows through said main supply means and third current responsive means arranged to oppose and -cancel the operating effect of the second current responsive means when current flows Si multaneously through the supplementary current supply means and the main supply means.

Other objects and advantages of my invention will be come apparent from the following description and accompanying drawings in which:

FIGURE 1 is a schematic diagram of a circuit utiliz ing my invention and including a main power supply device together with a single supplementary device, and

FIGURE 2 is a schematic diagram of the circuit showing the utilization of my invention in an arrangement wherein a plurality of supplementary current supply dcvices are utilized with the main power supply device.

As indicated previously, an alarm system utilizing my invention is adaptable to a wide variety of electrical circuits. In the present instance, however, it is shown in as a communications system, to the battery upon failureV of the alternating current source. Upon restoration of the A.C. supply the load is again provided with rectified current and the battery is again brought back to full charge and maintained on standby status.

As shown in FIGURE 1 the system includes a main, continuously operating, constant voltage device having input terminals 11 andl output terminals 12. A supple- .mentary current supply device 13 is likewise provided with input and output terminals 14 and 15 respectively. B'oth devices are provided with connections to a suitable source of alternatingcurrent indicated at 16.

`As shown in FIGURE 1, the input terminals of each 01:" the. charger-rectitier devices 10 and 13 are connected inl parallel with the alternating current source 16.

'In order Ithat the input to the current supply device 13 may be interrupted in a manner to be described presently, an input switch y17 having a make contact 18 is provided in the lead 19 connecting the input circuit of device 13 with the source of alternating current. Thus it will be se'enthatat all times, the device 10 is connected to the source of alternating current while the device 13 may hey intermittently connected or disconnected depending on v the position of the switch 17.

The positive, direct current output terminals of devices 107ancly 13 are connected in parallel with each other and to the load terminals 20 through lead 21 in which a. current responsive output relay 22 is series connected. This relay 22 y operates the switch 17 when current of a predetennined magnitude, preferably, substantially that of the outputlrating of the device 10, ows through that device.

yThe negative, direct current output terminals of the devices 10 and 13 are also connected to the load through windings of a relay 23. These windings comprise electromagnetically opposed sections 24 and 25 between which is disposed an intermediate tap 26 connected to the load throughv a lead 27. Aswill be seen presently, the winding` 24 serves to counteract the operating action of relay 23'I when cur-rent flows therethrough. If desired, the inter mediate .tap` may beeliminated and the winding sections 24 and 25 isolatedfrom one another in a manner well known i-nthe art.

Analarm circuit 28 of any suitable character and including eithervisible or audible alarm means, or both, includes a` normal-ly open switch' 29 having a make contact 30.

`While thevarious elements of my circuit may be calibratedAV to handle current of any desired magnitude, let it -be assumed, -for purposes of the present description, that the constantvoltage device 10 has a rated current output'o-fl 6 amperes while the rated. output of device 13 isi3V amperes.` Under these circumstances the winding of out-putl relay 22 is so arranged that the switch 17 in the lead .1-9 is closed when a current of substantially 6 amperes traversesthe winding. VWhen the switch 17 is in the posi-tion shown in FIGURE 1 the main device 10- is supplying the loadfrom itsV positive output terminal, through the winding of relay 22, the lo-ad, intermediate tap 26 and winding section 24 ofthe relay 23. So lo-ng as the-loadrdemand is such that less current than the operate value of relayI 22 is supplied by the device 10, the relay 22 is released and the device 10 alone supplies the load because of the open-condition of input switch 17.

However-,as the load increases and current of a magnitude greater than 6 amperes is required, the relay 22 will operate to close the switch 17 and thus incorporate thefcurrent supply device 13 in the circuit. Under these circumstances the load carrying capacity of the entire circuit has been increased to 9 amperes and thus the greater4 load Vcanbe accommodated.

Under the above described overloadrconditions current through the device 10 still traverses winding section 24 of the relay 23 while current through the current supply device 13 passes from the positive output terminal thereof,..through the load, the intermediate tap 26, winding sectionV of relay 23 and back to the negative input termittalthereof.

As previously indicated, due to the manner in which the coil sections 24 and 25 are connected into the circuit, their electro-magnetic effect will be in opposition whereby the net electro-magnetic effect of the relay 23 when sections 24 and 25 pass current isy reduced and the switch 29 therefore remains in the open position shown. Under these circumstances no alarm is created, indicating that the constant voltage device 10 and the current supply device 13 are both satisfactorily and operatively connected into the circuit.

Assume now that the current supply device 13 is-called upon by operation of the switch 17 in the manner p reviously described and also that, due to internal conditions or for some other reason, the device 13 is inoperative and thus unable to respond to the requirement that it aid the constant voltage device 10. It will be seen that under these circumstances no current will traverse the winding section 25 of relay 23. At the same time current through the constant voltage device 10 traverses the winding section 24. Under these conditions the elec tro-magnetic elect of the winding 24 will be unopposed by that of the winding section 25 and thus switch 29y Will be closed to energize the alarm circuit. This `condition of the alarm circuit then, correctly indicates that the constant voltage device 10 is operating satisfactorily but passing excessive current while the current supply device 13 has been called upon to supply the excessive current requirement of the load and has failed to do so. l

In the circuit described above it is preferable that the winding 24 of the relay 23 be so arranged that, when unopposed by the winding 25, it operates the switch 29 at about 6.5 to 7 amperes.

In other words, while the winding bf relay 22 is ar ranged to operate at substantially the rated output of the constant voltage device 10, the winding` 24 is arranged to operate the relay 23 at a current slightly higher than the operate value of the winding of relay 22. It will be understood of course that the opposing winding 25 is soy constructed asl to reduce the electro-magnetic elect,A ofwinding 24, therebyv to reduce theI total tractive effort when the current supply device 13vis operating'. ,p l

In the form of my invention shown in FIGURE` 2 there is provided the main, constant voltage device 1-0,Y

to accommodate the extra current supply'4 devices, and serving functions similar to those already described, are

indicated by similar numbers and a suflix. In the circuit of FIGURE 2 the alternating current Input leads and the input terminals of the constant voltage device 10 and the 'current supply devices 13, 1-3a andi- 13b are parallel connected in the manner previously described. Similarly the input circuit to each currenty sup# ply device' is provided respectively with input switch means 17, 17a and 17b and input switch operating means comprising, respectively,l relays 22, 22a and 22b. The operation of these components is similar to that previously `described in conjunction with the circuit of FIG- URE l.

In this form of my invention the alarm circuit isy provided with alarm switches, each of which is companion to one of the current supply devices as shown at 29, 29a and 29b. Additionally, each switch is provided with an' operating -relay 23, 23a and 23b provided with awindingmcluding two sections as previously described, each winding section on eachV relay being separated by intermediateV and 25, 25a and 25h respectively may be isolated from one another.

'It will be noted that inl the. circuit OFIGURE- 29 the' negative terminal of the constant voltage device is connected to the load circuit through the series connected winding sections 24, 24a land 24b while the positive output terminal is connected to the other side of the load through the serially connected windings of relays 22, 22a and 22b.

Referring to the alarm system provided in this circuit it will be seen that the intermediate taps 26 and 26a of relay 23 and 23a respectively are connected to next succeeding relay winding by means leads 31 and 31a respectively, the tap 26b then being connected to the load through lead 31b.

For the purpose of describing the operation of the circuit of FIGURE 2, let it be assumed that the output current rating of the constant voltage device 10 is 12 amperes while the current rating of the three supplementary devices 13, 13a and 13b is 3 amperes each. It will thus be seen that if the winding of relay 22 is arranged so that the relay operates at 12 amperes, the switch 17 will close when this magnitude of current is passed by the constant voltage device thereby to incorporate constant voltage device 13 and its additional 3 ampere capacity into the circuit.

'I'he circuit is now capable of safely passing 1S amperes to the load. Should this maximum current capacity be exceeded, and if the winding of relay 22a is arranged to operate the relay at substantially 15 amperes, it will be seen that when this increased current capacity is exceeded, current supply device 13a "willbe incorporated in the circuit by operation of switch 17a. At this time the circuit is capable of passing 18 amperes to the load.

When the 18 ampere load is exceeded, the winding of relay 22b being arranged to operate at 18 amperes, the switch 17b will be operated to incorporate the third current supply device 13b into the circuit. At this point of the operation the maximum, 2l ampere current capacity of the system shown has been attained.

From the foregoing it will be seen that each input relay is thus arranged to operate at a current value equal to the rated output of the main device 10 plus the rated output of all supplementary devices preceding it in the circuit.

yIn the case of this sequential incorporation of successive current supply devices into the circuit as the load current increases, it will be seen that the negative or return path from the load to the main device 10 includes the left hand winding 24, 24a and 24b of each alarm relay. The lead path for each supplementary device then incorporated in the circuit will be the respective Winding section 25, 25a or 25b, the latter passing current rendering the associated main supply Winding ineffective to close the effective alarm switch. The winding section 25, 25a or 25b of a supplementary device incorporated in the circuit will of course be incapable of opposing its associated main supply winding. However, as will be seen from the above example the load requirement is of a magnitude below the operating value of the companion alarm switch relay whereby insuicient current traverses the main supply winding for accomplishing an alarm switch closing operation. For example, assuming that the constant voltage device 10 is operating satisfactorily and the load then requires 16 amperes, current supply device 13 will be incorporated into the circuit by operation of switch 17 to give 15 ampere capacity and current supply device 13a will be included in the circuit through operation of switch 17a because relay 22a is calibrated to operate at 15 amperes. Under these circumstances current will ilow from the positive output terminal of current supply device 13a, through the winding of relay 22b into the load, from the negative load terminal through intermediate tap 2Gb and winding section 24b of relay 23h, through lead 31a and intermediate tap 26a and then through winding section 25a of relay 23 to the negative output terminal of current supply device 13a. Similarly, return current flow is completedY to device 13 through winding section 25. It will be understood that under 6 these conditions, return current ow to the device 10 will be through windings 24b, 24a and 24.

Considering the current values to the load as being those assumed above, let it be further assumed that winding sections 24, 24a and 24b are `arranged so that, if unopposed, they operate their respective relays at 13 amperes, 16 amperes and 19 amperes respectively. Thus it will be seen that each of the alarm switch operating relays 23, 23a or 23b is arranged to operate and close its respective alarm switch at a current value of approximately l ampere above the full load rating of the constant voltage device 10 plus that of the current supply devices preceding its companion current supply device in the circuit. ln the above example, device 13b being dormant, no current will flow through opposing Winding 25b. HOW- ever, winding 24b will be ineffective to operate its switch since it is arranged to operate at 19 amperes and is receiving only 16 amperes. On the other hand, windings 24 and 24a are rendered ineffective by the opposing electro-magnetic effect of windings 25 and 25a respectively since both of the companion supplementary devices are passing current.

lt will be seen that if the load calls for 14 `amperes the current supply device 13 will be incorporated in the circuit and if operative, coil sections 24 and 25 will both be energized as return paths to have counteracting electromagnetic effect on the relay 23 of the switch 29. If however, the current supply device 13 is required in the circuit and is inoperative and thus fails to assume its portion of the load, no current will flow through winding 25 and the alarm will be energized by closure of switch 29 immediately upon the passing of 1 ampere of excess current, namely .13 amperes, by the constant voltage device 10.

Assuming now that the load calls for 20 amperes, current supply devices 13, 13a and 13b will be sequentially incorporated in the circuit by their respective input relays 22, 22a and 22b and respective switches 17, 17a and 17b. Under these circumstances should one of the constant current devices be inoperative, no return current will flow through its respective, companion winding sections 25, 25a or 25b. This results in the associated winding section 24, 24a or 24b operating the respective relay 4and thus closing the respective alarm switch 29, 29a or 29h when the current through the respective winding 24, 24a or 24b reaches a magnitude of approximately 1 volt above the rated output of the main device 10 and the current supply devices preceding its companion current supply device in the circuit.

In the above example, assume that an intermediate current supply device such as 13 is inoperative. It will be seen that, due to the arrangement of relays 22a and 22b at operate values of 15 and 19 amperes respectively, sufficient current will not be supplied, because of the inoperativeness of the device 13, to operate these relays 22a and 22b. Hence, more than 13 amperes will tend to flow through winding 24, which is companion to constant voltage device 10, with the result that the alarm switch 29 will be operated. In other words, if the circuit is operating under conditions requiring, for instance, devices 10, 13, 13a and 13b then, should any intermediate current supply device 13 or 13a be rendered inoperative, the necessary current to hold the succeeding switch 17a or 17b closed will not ilow. Therefore, the disabled device and all succeeding it in the circuit will be disconnected.

It is to be noted that upon an increase of load current beyond the combined capacity of all of the devices shown in FIGURES l or 2 the alarm circuit shown herein will operate as described to energize the alarm and the individual devices will be self protected internally by appropriate cut-off means. Usually the constant voltage device is provided With current limiting means whereby it is inherently protected against such an overload condition while the constant current devices are provided with 7 thermal cut-off means. In the event that all of the devices in the circuit are brought into operation and load current continues to rise it will be seen that the constant current devices will be rendered inoperative by the thermal cut-off means and this disabling action will immediately energize the aarm circuit in the manner described.

While specific operate values of the current responsive devices haveV been'given herein by way of explanation, it'willbe understood that any suitable values may be designed nto a particular circuitto meet the specitic needs thereof.-

From thel foregoing it will beseen that I have provided an electrical circuit including a main power supply device together with aiding or supplementary power supply devices and including an alarm circuit wherein, as load current demand rises, the supplementary current supply devices are sequentially incorporated into the circuit. The arrangement is such that succeeding supplementary'devices are removed from the circuit in the event of intentional or unintentional disability of a preceding supplementary device, the alarm circuit being energized upon failure of any of the supplementary supply devices inthe presence of continued operation of the main device in the presence of excessive current llow.

While my invention is described herein in conjunction with an electrical circuit in which the main device has constant voltagel characteristics and the supplementary device or devices are for current supply purposes it will be understood that the invention is also appliable to an electrical circuit in which the supplementary devices have constant voltage characteristics.

Additionally, it will be understood that while there is shown herein an alarm circuit energized by overload of a main supply device and simultaneous failure of a supplementary device, an ancillary operating circuit capable of performing other functions when energized may be utilized; For instance such a circuit might be connected' toV an independent system for incorporating the latter into the circuit upon fai'ures described above.

It-willbe understood that the embodimentsv shown herein are for explanatory purposes and may be changed or modied without departing from the spirit and scope of my invention as set forth in the claims appended hereto.

What I claim is:

l. In an electrical circuit adapted to be connected between a source of electrical energy and a load, a rst current passing device having input and output terminals, a second current passing device having input and output terminals and operableon demand of said first device when the latter passes current substantially equal to its rated output, means for connecting the input terminals" of said devices in parallel with the source of electrical energy, means for connecting output terminals of said devices in parallel with each other and to the load, iirst electro-magnetic means connected in series with and between similarly poled output terminals of said devices, a` switch connected in series with said source and between input terminals of said devices, said first electro-magnetic means being arranged to operate upon passage of a magnitude of current substantially equal to the rated current output of said first device to close said switch and connect said second device into the circuit, second electro-magnetic means including a winding having two sections and an intermediate tap disposed therebetween, means connecting said intermediate tap to the load terminals, the ends of said winding being connected respectively to similarly poled output terminals of said devices whereby one of said winding sections is serially connected between the output of one of said devices and the loadand the other section is serally connected between the 'output of the other of said devices and the load, an alarm circuit, aswitch connected serially therein for operation by said second electro-mag netic means, said second electro-magnetic means being arranged so that saidwinding section connected to` said first device operates said second electro-magnetic means t0 close said alarm switch when the second device is i11- operative and current through the irst device tov the load, is substantially equal to its rated current output, said winding section connected to the second device being ar1 ranged to oppose-the electro-magnetic effect of said other winding section when current through the load terminals is passed by both said tirst and said second device'.

2. In an alarm system for an electrical circuit adapted for connection between a sourceY of electrical-energy and a load, a first current passing device havinginput and output terminals, a second current passing device having input and output terminals and operable on demand of said first device when the latter passes current exceed ing a predetermined magni-tude, means for connectingl said input terminals in parallel with the source of elecV trical energy, means for connecting said output terminals in parallel with each other and to said load, current responsive means for connecting the second of said devices in the circuit upon passage of current of said predetermined magnitude through said iirstvdevice, an alarm circuit including switch means connected serially therein, means for closing said alarm switch means when excessive current flows through the first device and the sec-` ond device fails to respond to the demand of said first device including electro-magnetic means having a winding, an intermediate tap on the winding, means for c0nnecting said tap to the load, means for connecting each end of said winding to similarly poled output terminals of the first and second devices'respectively, whereby said winding sections on each side of the tap are in electromagnetic opposition and traversed respectively by current from said rst and second devices to the load terminals when both devices are operating, said winding section connected between the intermediate -tap and said irst device being arranged to operate said electromagnetic means to close said alarm switch when passing current of saidpredetermined magnitude while said secondarie` vice is inoperative.

3. In an electrical circuit adapted for` connection be'-n tween a source of electrical energy and a load, in combination, a tirst current passing device having input and output terminals, a second current passing device having input and output terminals and operable on demand of said rst device when the later passes current exceeding a predetermined magnitude, means for connecting saidl source of electrical energy in parallel with the input terminals of saiddevices, means for connecting the loadf in parallel with each other and to the output terminals" of said devices, input circuit interrupter means connected in series between the source and the inputV terminals of said second device, first current responsive interrupte operating means connected between an output terminal of said iirst device and the load for closing the input-circuit interrupter and energizing said secondl device upon predetermined increase of current passing through said rst device to the load, an alarm circuit, alarm circuit interrupter means connected in series in said alarm circuit, second current responsive interrupter operating means' connected between -the source and the load through said irst device, third current responsive interrupter operating means connected ybetween the source and the load through said second device, said third current responsive means being arranged lto oppose the action of said second cur rent responsive means when current passes from the source to the load through said first and second devices, said seco-nd current responsive means being arranged to' close said alarm circuit interrupter means when said sec ond device is inoperativeand current exceeding a predeter-v mined magnitude passes from the source to the load terminals through said firstY device.

4. In an electrical circuit of the type adapted to be connected between a source of electrical energy and a load and having main electricalsupply means andY a plurality of supplementary electrical supply means, in combination, means for connecting the source to the load through the main supply means, means for intermittently connecting the source and the load sequentially through the respective supplementary supply means in aiding relationship to the main supply means upon ow of current -in excess of current of a predetermined magnitude through the load, an alarm circuit, circuit interrupter means connected serially therein, there being separate interrupter means for each of said supplementary means, means for connecting said interrupter means in parallel with each other, relay operating means for each of the interrupter means, each of said relay means including first and second windings disposed in opposing electromagnetic relation to one another, means for connecting said main supply means to the load through said irst windings, means for connecting said supplementary supply means to the load through the respective second winding, said irst windings being arranged to operate the respective interrupters to energize the alarm circuit when current in excess of current of said predetermined magnitude flo-ws through the main supply device, said second windings being arranged to electro-magnetically oppose the electro-magnetic etiect of the respective first winding when current tiows from the source to the load through the respective supplementary supply means and said main supply means.

5. In an electrical circuit of the type adapted to be connected between a source of electrical energy and a load, a plurality of current passing devices each having input terminals connected in parallel with the source and output terminals connected in parallel with each other and to the load, at least one of said devices operating substantially constantly to pass current from the source to the load, others of said devices serving as supplementary devices and operating intermittently as the load current requirements attain substantially the total current output rating of the constantly operating device and any of the then operating supplementary devices, an alarm circuit, alarm switch means connected serially in said alarm circuit, input switch means connected serially between the source and the input terminals of the respective supplementary devices, current responsive, input switch operating means connected serially between the output of the constantly operating device and the load and between said constantly operating device and the respective supplementary device, said input switch operating means being arranged to operate respective input switch means to close the input circuit to the respective supplementary device upon predetermined increase in load current, current responsive alarm switch operating means connected serially between the source and the load through the constantly operating device and the respective supplementary devices, said alarm switch operating means being arranged to exert negligible electrical elect to close the alarm switch when the current through the constantly operating device is above a predetermined magnitude and the respective supplementary devices are operating in response to closure of the respective input switch means and to close the respective alarm switch means when a respective supplementary device fails to pass current in response to closure of the respective input switch means.

6. In an electrical circuit of the type including main power supply means and supplementary power supply means adapted for connection between a source of electrical energy and a load, said supplementary supply means being adapted to supply additional current to the load when load current requirement exceeds a predetermined limit, said supplementary supply means and said main supply means having input terminals connected in parallel with the source and having output terminals connected in parallel with each other and to the load, in cornbination, input switch means connected respectively be tween the source and the input terminals of the respective supplementary supply means, current responsive input switch operating means connected respectively between the output of the main supply means and the load and being arranged to operate and close said respective input switch means upon passage of current of predetermined magnitude through said main supply means and any then operating supplementary supply means, an alarm circuit, alarm switch means connected serially in said alarm circuit, alarm switch operating means respectively connected serially between the source and the load through said main supply means and respective supplementary supply means, said alarm switch operating means being arranged to close the respective alarm switch means when current through the main supply means and any then operating supplementary supply means exceeds said predetermined limit and the respective supplementary supply means is inoperative.

7. In an electrical circuit of the type adapted to be connected between a source and a load, having main and supplementary supply means and means for continuously connecting said main supply means between the source and the load when the circuit is energized, in combination, lirst current responsive means for connecting respective supplementary supply means between the source and the load upon increase of load current to a value substantially that of the rated current output of the main supply means and any supplementary supply means then connected between the source and the load, an alarm circuit having circuit interrupter means connected therein, interrupter operating means including second current responsive means adjusted to operate at a current liow above the rated current output of said main supply means and any sup-plementary supply means then connected between the source and the load, means for connecting said second current responsive means between the main supply means and the load, third current responsive means and means for connecting said third current re sponsive means in opposition to said second current responsive means between the respective supplementary supply means and the load to oppose the interrupter operating effect of the respective second current responsive means when current ows from the source to the load through said main supply means and through therespective supplementary supply means. 1

8.' In an electrical circuit of the type adapted to be connected between a source of electrical energy and a load and having main electrical supply means and supplementary electrical supply means, in combination, means for continuously connecting the source to the load through said main supply means, means for intermittently connecting the source to the load through said supplementary supply means in aiding relation to said main supply'means including input switch means, means for closing said input switch means including -current responsive means connected in series between the main supply means and the load, an alarm circuit including alarm switch means serially connected therein, return circuit means connecting the load respectively to said main and said supplementary supply means including current responsive alarm switch operating means, said alarm switch operating means including a first element energized by current ow of predetermined magnitude between the load and said main supply -means to close said alarm switch means and a second element energized by current flow between the load and said supplementary supply means to oppose said tirst element for rendering the same ineffective to close said alarmv switch when current liows simultaneously from the load to the main supply means and to the supplementary supply means.

9. In an electrical circuit of the type adapted to be connected between a source of electrical energy and a load and having main electrical supply means and supplementary electrical supply means, in combination, means for connecting the source to the load through said main supply means, means for additively, intermittently, connecting the source to the load through said supplementary' supply means upon increase of loadcurrent in excess of that of a predetermined magnitude, an alarm circuit, -alarmcircuit interrupting means connected serially therein, means for operating said alarm circuit interrupting means including iirst current responsive means connected serially between the load and said main supply means and energized by flow of current in excess of a predetermined magnitude -between the load and said mainv supply means,second current responsive means connected` serially between the load and the supplementary supply means inoperative opposition to said first current responsive means and energized by ow of current from the load to said supplementary supply means whereby,

through opposing action of said first and second current responsivemeans, said interrupting means is inoperative upon simultaneous ow of current between the load and the source through said main and through said supplementary supply means and is operated to complete the alarm circuit when current in excess of a predetermined magnitude flows from between the load to the main supply means while said supplementary supply means is inoperative to pass current from the source to the load.

10. In an electrical circuit of the type adapted to be connected between a source of electrical energy and a load and having main and supplementary electrical supply means, means for connecting the main supply means between the source and the load when the circuit is energized and means for intermittently connecting the supplementary supply means between the source and the load in response to an increase in load current demand to a predetermined magnitude, in combination, an alarm circuit, alarm circuit interrupter means therein, interrupter operating means including rst current responsive means connected between the main supply means and the load for` operating the interrupter means to energize the alarm circuit` upon loadcurrent requirements exceeding aA-predetermined magnitude and second current responsive meansconnected between the supplementary supply means and the load for counteracting the operating effect of the firstA current responsive means upon current ow through the t supplementary supply means.

l1, In an electrical circuit of the type adapted to be connected between a source and a load and having main electrical supply means, supplementary electrical supply means, means for continuously connecting the source to the loadthrough said main supply means when said circuit isenergized and means for intermittently connecting the source to the load through said supplementary supply means inn aiding relation to the main supply means uponlflow of loadcurrent inexcess of current of a pre determined magnitude through said main supply means andn through any then operating supplementary supply meansincombination,. an alarm circuit, alarm circuit interrupting means connected therein, relay means operatively associated with respective interrupting means, said relay means including respective current responsive, elec-- tro-magnetically opposed winding sections, means forconnectingv said main supply means to the load through one of said winding sections, means for connecting respective supplementary supply means to the load through the respective opposed winding section.

l2. In an electrical circuit of the type adapted to be connected between a source of electrical energy and a load and having main and supplementary electrical supply means, in. combination, means for connecting the main supply means between the source and the load when.

the circuit is energized, means for intermittently connecting the supplementary supply means between the source .and the load in response to an increase in load current to a predetermined magnitude, anv alarm circuit, alarm circuit interrupting means connected therein for controlling the ow of current therethrough, means for operating said alarm circuit interrupting means including a rst current responsive element connected between the source and the load through said main supply means for operating said interrupting means upon llow of load current in excess of that of said predetermined magnitude and a secondcurrent responsive element connected between the source and the load through said supplementary supply means for counteracting the operating eiect of said first current responsive element upon ow of current through said supplementary supply means.

13. In an electrical circuit of the type adapted tobe connected between a source of electrical energy and a load and having main land supplementary electrical supply means, in combination, means for connecting the main supply means between the source and the load whenv lthe circuit is energized, means for intermittently connect# ing the supplementary supply means between the source and the load in response to an increase in load current' to a predetermined magnitude, an ancillaryelectrical circuit, interrupting means in said ancillary circuit for controlling the ilowof current therethrough, means for operating said interrupting means including' a irst current responsive element. connected between the source .and the load through said main supply means for operating said;

interruptingv means upon flow of load current' in excess of that of said predetermined magnitude and a second current responsive element connected between the source and the load through said supplementary supply means for counteracting the operating effect ofA said first cur-l Williams Nov. 29, 1927 Hanley Apr. 3, 1934 

